[Effect of calcium channel blocking agents on methacholine-induced airway hyperreactivity in subjects with asthmatic...

Methacholine-induced airway reactivity was studied in patients with asthmatic bronchitis, asthma or cor pulmonale during remission and the parameters (especially of cor pulmonale) were significantly higher than those of control subjects. The change was negatively relevant to FEV1 V25 V50 and MMF. The subjects were given two tablets of placebo, verapamil (80mg), nifedipine (20mg) or diltiazem (60mg) orally and double-blindly. In every subject, PC20 and lung functions were tested 2 or 3 hours after administration. These agents did not dilate bronchi. However, airway reactivity to methacholine was attenuated by nifedipine in asthmatic bronchitis and by diltiazem in asthma (P less than 0.05). However all the three agents did not reduce airway reactivity of cor pulmonale.